Control means for thermo-compressors



July 26, 1938. J. KIRGAN 2,124,620

- I I coN'T RoL MEANs FOR THERMO-COMPRESSORS Filed Feb. l6, 1937 iza f mwi fril- INVENTOR. John [firazz, BY

Hrs ATTORNEY Patented July 26, 1938 UNITED STATES CONTROL MEANS FOR THERMO- COMPRESSOR-S John Kirgan, Easton, Pa,, assignor to Ingersoll- Rand Company, Jersey City, N. J., a corporationof New Jersey I Application February'16, 1937, Serial No. 125,996 a 4 Claims.

This invention relates to thermo-compressors, and more particularly to devices acting responsively to pressure conditions in a thermo-compressor to control its operation.

A few of the objects of the invention are to prevent waste of power in a thermo-compressor, and to assure positive control of the power supply.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing, in which similar reference characters denote similar parts,

Figure 1 is a view, in elevation and partly in section. of apparatus embodying control 'means constructed in accordance with the practice of the invention, and

Figure 2 is a similar View showing a modified form of the invention.

Referring more particularly to the drawing and especially to Figure 1, the invention is shown embodied in a refrigerating system comprising an evaporator, fragmentarily shown at II], a condenser I I, and a thermo-compressor, indicated in general by I2, connected to convey vapor from the evaporator to the condenser.

The thermo-compressor may be of any desired construction, and is shown as including a casing l3 forming a passage|4 opening at one end into the evaporator l0 and at the other end into the condenser Discharge nozzles for steam or other power fluid, one being shown at l5, are positioned in the passage |4 near the end which opens into the evaporator. The casing l3 may be sealed around the nozzles in any well known manner, and a pipe I6 provided with a control valve |1 will serve to convey steam to the nozzles.

In practice both the evaporator l0 and condenser I I may be kept under high vacuum by the compressor 2 and by a condenser vacuum pump (not shown), and refrigerant exposed to the vacuum in the evaporator may be partially vaporized and chilled for refrigerating purposes.

In accordance with the practice of the invention, and to obviate waste of power in the compressor, suitable means are provided for automatically and accurately controlling the amount of steam admitted to the nozzles |5. In its preferred form, a throttle valve I8 is interposed in the steam supply pipe l6 and arranged to be automatically controlled by a power medium, the strength of which is varied in accordance with pressure conditions in the compressor.

In the construction illustrated, the valve I8 is within a casing l9 and is preferably provided with a stop to prevent its complete closure. The stem 2| of the valve extends outside of the casing l9 and terminates in a head 22 to provide an abutment for a spring member 23 which bears against the casing 9 and acts to urge the valve toward open position.

The head 22 of the valve stem is in abutment with a diaphragm 24 against which pressure may be applied for moving the valve IS in opposition to the spring 23. A casing 25 to which the diaphragm is affixed, forms a chamber 26 between itself and the diaphragm, and a pipe 21 serves to convey suitable pressure fluid, compressed air, for example, from an external source (not shown) to the chamber 26. A small vent 29 in the casing 25 serves to prevent trapping of pressure fluid in the diaphragm chamber.

A control member comprising a valve 28 and a valve casing 30, is interposed in the pipe 21 to determine the pressure of the fluid delivered to the chamber 26. This valve is shown as of the needle type, and the stem 3| of the valve extends outside of the valve casing and may be provided with a collar 32 to serve as an abutment for a spring 33. The spring also bears against the casing 38 and acts to urge the valve 28 toward open position.

A pressure-responsive device for actuating the valve 28 is illustrated in the form of a U-shaped manometer vessel 34 in which is placed a. quantity of mercury 35 or other fluid medium. One'arm of the manometer forms a chamber 36 which may be sealed, or if desired, placed in communication with the evaporator ID or the inlet to the thermocompressor passage I4. The other arm of the manometer forms a chamber 31 into which a pipe 38 leads from the condenser II or from a. point near the outlet of the passage l4.

A piston or float member 39 is preferably positioned in the chamber 31 to be actuated by the mercury 35. A rod 40 connected to the float extends through a gland to the outside of the vessel 34, and a rod 4| is pivotally connected at one end to the float rod 48 and at its other end to the stem 3| of the valve 28. The rod 4| is also fulcrumed, as indicated by 42, intermediate the aforesaid pivotal connections to enable the motion of the float 39 to be transmitted from the rod. 40 to the valve stem 3|.

In operation, the inlet and discharge pressures of the thermo-compressor |2 will rise or fall as the amount af vapor formed in the evaporator I0 increases or decreases due to variations in refrigerating load, or as the pressure in the condenser varies due to changes in cooling water temperature, for example.

The mercury in the chamber 31 will be subjected to whatever pressure conditions exist at the discharge end of the compressor, and the chamber 36 may be under vacuum, as by prior filling of the manometer with mercury and inverting to the position shown. When the discharge pressure increases, the mercury will be depressed in the chamber 31 and forced into the chamber 36. The float 39 will fall and its motion will be transmitted by links 48 and 4| to 7 move the valve 28 toward closed position. Less move from one manometer chamber to the other pressure fluid will now be supplied to the chamber to that of the steam supplied to the valvel8, will sures increases. ,pressure. fluctuations are made use of to effect tepper steam to the compressor only in the amounts necessary, and waste of steam is thus p r l f dr I be delivered to the nozzles l5, to enablethe compressor I2 to overcome the increased. discharge pressure. Whenthe condenser pressure again decreases, the pressure onthe diaphragm 22 will be increased to move thevalve l8' towardclosed" position, and thusthe stean'i maybe regulated in to which this invention appertains that other arrangements and combinations may be made for accordance with the'demand therefor;

If it is desired that'the ,valve 18' be actuated in accordance with the pressure differential between the manometer chamber 36 and the evaporator 10, and the mercury will, inthis instance,

VA partifiextends from the bottom of the movable ,vessel and carries a rodfllpivotally connected to the rod 451 for actuating the valve 28,'and a head 48 at the end of the rod 41 forms an abutment against which a spring 49 bears to resist the downward movement of the vessel :44.

The vessel 43 encloses a chamber may be sealed, or if desired, placed in communication with the evaporator. 10, and the vessel 44 encloses'a chamber 31 which isconnected by a 'flexible tube -withthe condenser l3. The flexible tube 5| between the-chambers 36 and 31"con- -nects the bottoms thereof and serves as a passage for conveying the mercury 35 from. one

chamber to the other; j 1 I V 'In operation, when condenser pressure increases the mercury isdisplaced fronrthe chamber 31' into the chamber-3,6 and theweight of themovable vessel and its contents is decreased. The spring 49 then causesthe container 44 to rise and the valve 28 to move towardclo'sed "position, and this-in turn decreases the pressure acting on the diaphragm 24 to-cause the valve 18 :to bemore fully opened. 7

'In thermo-compressors which operate at both inlet and discharge under high vacuum such as is encountered in water-vapor refrigerating systems, it has been found that the. fluctuations in the 'inlet and discharge pressures are of suchsmall.

magnitude, that they cannot be conveniently directly appliedto actuatedevices for controlling the flow of steam to the compressor. Accordingly, provision is made for multiplying the variations in these pressures; and vfor using the ,increased variation to controls. suitablepower The evacuating capacity of a thermo-com- 36 which pressor is well known to be constant for a given. suction pressure, and the power supplied to the compressor need 'only be increased if the suction pressure decreases; the discharge pressure. increases, or'the differential between the two pres- In the present invention these "I t1will'belapparent to those skilled in the" art accomplishing like results.- It will be understood,

' thereforathat the scope and spirit of the inven:- tion is not to be limited to the specific vforms ,described, but is to be interpreted only by the terms-in which the appended'claims are. ex-

. pressed. r V

' 1, The combination with a thermo-compressor, and means to admitpower fluid to the compressor including a control member, of means to admit a power medium to the control member for actuat- .ing the same, a U-shaped vessel for a transmission medium, means actuated by the transmission medium to control the last-named means, means communicating between the vessel and the compressor to subject thejtransmission medium solely. to the total discharge pressure of the compressor, thereby to actuate the transmission medium. r

2 The combination with a thermo-compressor,

and'means to admit power. fluid to the com pressor including a control member, of means to admit a power medium to the control member for actuating the same, a U-shaped vessel containing a transmission medium, means actuated by the transmission medium to control the last-named means, means to seal one arm of the vessel, and

latter medium.

3. The combination With'a thermo-compressor,

and means to admit power fluid to-the compressor including a control member, of means to admit a power medium to the control member for actuating the same, a device to control the lastnamed means separate vessels having a connection fortransmitting a fluid medium therebetween, and means to subject the fluidmedium inethe vessels to pressure conditions in the com- ;pressor for displacingthe fiuidmediumirom one vessel to the other, one of said vessels being in fixed position, and the other vesselbeing movj able and having connections to control said device in accordance with the amount of fluid medium present in the latter vessel.

. 60 4. The combination with a thermo-compressor,"

and a means-to admitpower fluid to the compressor including .a control member, of a'means JOHN KIRGAN.

compressor, and means acting to control the ad- 0 mission means in response to variations of said liquid level. 

